Effect of ionic gums and dry heating on physicochemical,morphological, thermal and pasting properties of water chestnut starch

Starch from water chestnuts (Trapa natans) was isolated and modified by dry heating and hydrocolloids [carboxy methyl cellulose (CMC) and sodium alginate]. Native and modified starches were evaluated for their physicochemical, pasting, thermal and morphological properties. Pasting and thermal properties were studied using Rapid Visco Analyzer (RVA) and Differential Scanning Calorimeter (DSC) respectively. Morphological properties were studied by Scanning Electron Microscopy (SEM). Modification of the starch by dry heating with and without gums reduced paste clarity and increased the water and oil binding capacity; solubility and swelling power decreased. Dry heating of native starch increased peak viscosity; however, with addition of CMC, peak viscosity decreased. Starch modified with CMC and 4 h heating exhibited lowest gelatinization temperature (T₀). Pasting characteristics of native water chestnut starch were largely affected by the addition of gums and/or heat treatment. Overall onset gelatinization temperature reduced with heat treatment and addition of gums. Morphological studies revealed no significant variation in starch granule size. Starch granules were seen agglomerated because of leaching of amylose and granule interspacing decreased with addition of gums.     

干热处理对荞麦淀粉物化和结构特征的影响

为了扩大荞麦淀粉在食品领域的应用,研究干热处理对荞麦淀粉物化特性和结构的修饰效果,将荞麦淀粉分别于120、130、140、150、160、170℃干热处理30 min.结果 表明:干热处理使荞麦淀粉的峰值黏度、最终黏度等RVA相关黏度参数、起糊温度、凝胶化起始温度、凝胶化峰值温度、凝胶化焓值、结晶度均降低,温度高于13...     

干热处理对玉米淀粉性质的影响

研究了干热处理前后玉米淀粉的性质变化,对干热处理前后淀粉的溶解指数、糊化特性、热力学性质、颗粒形貌和结晶结构进行了测定及分析。结果表明,当干热处理温度低于150℃时,与原淀粉相比,干热淀粉的溶解指数、黏度均降低,糊化温度降低;当干热处理温度为150℃时,淀粉的溶解指数升高、黏度降低、糊化温度降低。干热处理后,淀粉表面出现凹坑,且颗粒间有黏结。      

干热处理对马铃薯淀粉—离子胶混合物理化性质的影响

将马铃薯淀粉与黄原胶、海藻酸钠、羧甲基纤维素钠(CMC)等混合后进行干热处理,制得热改性马铃薯淀粉。研究干热处理对马铃薯淀粉分别与3种离子胶混合制成的混合物的物理化性质的影响。结果表明:经干热处理后,马铃薯淀粉—CMC和马铃薯淀粉—黄原胶混合物的凝胶硬度、胶着性和咀嚼性均显著增加,热稳定性显著增强。而马铃薯淀粉—海藻酸钠混合物凝胶的质构特性和热稳定性没有显著变化。红外测定结果表明,与离子胶混合,再经干热处理后后,马铃薯淀粉的红外特征峰向低波长移动,分子间的氢键增强,表明了淀粉与离子胶在干热过程中发生了相互作用。     

黄原胶辅助干热改性淀粉纳米颗粒的理化特性研究

以玉米淀粉纳米颗粒为原料,通过黄原胶辅助对其进行干热改性,以便改善淀粉纳米颗粒的加工特性,扩大其应用范围。采用差示扫描量热仪(DSC)、流变仪、X-衍射分析仪、透射电镜(TEM)等对干热处理前后的纳米颗粒与黄原胶共混物的热特性、流变特性以及微观结构进行了研究。结果表明,经黄原胶辅助干热处理后,淀粉纳米颗粒的糊化温度和焓值显著增加,表明纳米颗粒的结构增强,热稳定性增加。与未经干热处理的样品相比,干热混合物的储能模量(G')值显著升高、而损失因子(tanδ)明显降低,表明干热处理后,淀粉纳米颗粒乳液的凝胶性增强,呈现更加偏向于类固体的性质。TEM结果显示,淀粉纳米颗粒的直径在100 nm左右,与黄原胶混合干热后,有聚集现象,且颗粒有缩小的趋势。本研究可作为淀粉纳米颗粒物理改性的一种新方法,为生产改性淀粉纳米颗粒提供参考。     

不同离子胶对玉米磷酸酯双淀粉性质的影响

研究了离子胶(羧甲基纤维素钠、海藻酸钠、卡拉胶、壳聚糖)不同添加量(0∶1、1∶9、3∶7)对玉米磷酸酯双淀粉糊化特性、凝胶质构特性、溶胀度和吸油率等性质的影响。结果表明,阴离子胶(羧甲基纤维素钠、海藻酸钠、卡拉胶)降低了玉米磷酸酯双淀粉的峰值黏度、衰减值;而阳离子胶(壳聚糖)使玉米磷酸酯双淀粉的峰值黏度、衰减值显著增加。阴离子胶使玉米磷酸酯双淀粉凝胶硬度下降,而壳聚糖则使其凝胶硬度上升。阴离子胶能促进玉米磷酸酯双淀粉的溶胀,但壳聚糖抑制其溶胀。壳聚糖使玉米磷酸酯双淀粉吸油率增加。离子胶对玉米磷酸酯双淀粉性质的影响,不仅与离子胶自身性质有关,而且可能与二者之间的静电作用密切相关。     

逆研磨对木薯淀粉理化性质的影响

采用贝利粉碎机对木薯淀粉进行机械活化,研究了逆研磨对木薯淀粉理化性质的影响。结果表明,逆研磨后,颗粒粒径变化很小,团聚颗粒更多,结晶结构无变化,溶解度增大,膨胀度、表观粘度减小,透明度变化不大,剪切稀化程度降低,Brabender黏度曲线由B型变为D型。     

自然发酵对高粱淀粉物化性质的影响

以高粱为原料,探讨不同发酵时间对高粱淀粉理化性质的影响。将高粱进行自然发酵0~15 d,探讨不同发酵时间对高粱的保水力、溶解度、透明度、直链淀粉含量以及淀粉的糊化、老化回生趋势的影响。结果表明:随发酵时间的延长,淀粉的保水力、溶解度小幅度的增加,而透明度呈降低趋势;自然发酵使高粱的直链淀粉含量增加;在不同发酵时间条件下,发酵淀粉的糊化温度较未发酵淀粉最高降低了0.64℃,而糊化焓最高增加34.42 J.g-1;淀粉的回生值与最终黏度均随发酵时间的延长而呈先减小后增加的趋势,其中发酵第6天淀粉的回生值较未发酵淀粉的回生值降低了783 m Pa·s。自然发酵后高粱淀粉的理化性质发生变化,淀粉的老化特性改善,更适宜生产利用淀粉老化特性制得的产品。     

抗性淀粉对淀粉理化性质和酶解速率的影响

将抗性淀粉和蜡质玉米淀粉按不同的比例混匀制成复配粉,研究不同含量抗性淀粉对复配粉的膨胀度、溶解度、糊化特性和酶解速率的影响。结果表明:随抗性淀粉含量增加,复配粉溶解度降低,膨胀度增大,酶解速率逐渐降低。快速黏度分析仪(RVA)分析表明:抗性淀粉所占比例增加,复配粉的糊化温度逐渐升高,抗性淀粉含量为60%时,糊化温度达到最高,为75.25℃,而峰值黏度、谷值黏度、末值黏度、衰减值和回生值逐渐下降,抗性淀粉含量为100%时,复配粉的峰值黏度、谷值黏度、末值黏度均达到最低。     

Effect of complexation of oxidised corn starch with mineral elements on physicochemical properties

The objective of this study was to determine the effect of complexation of oxidised starch with mineral elements on its physicochemical properties. Corn starch was oxidised with sodium hypochlorite and, afterwards, modified with ions of potassium, magnesium and iron. Thus, native and modified starches were analysed for: contents of mineral elements, colour parameters (L*a*b*), water binding capacity and solubility in water at temperature of 60 and 80 °C. Thermodynamic characteristics of gelatinisation by DSC, molecular weight distribution by GPC, intrinsic viscosity and pasting properties by RVA were studied. The efficiency of incorporation of metal ions into oxidised corn starch was about 30%, 20% and 20% for potassium, magnesium and iron ions, respectively. The complexation with potassium ions caused the greatest changes in the molecular weight distribution and the intrinsic viscosity of starches and viscosity of starch pastes. Only modification of starch with iron ions affected the colour parameters of the starch. Incorporation of metal ions into starch resulted also in changes in its water binding capacity and solubility in water.     

铝盐对豌豆淀粉凝胶理化性质的影响研究

以豌豆淀粉为原料,采用质构仪、色差仪、傅里叶变换红外光谱仪等对不同质量分数的铝盐与豌豆淀粉共混体系的凝胶特性及微观结构进行了系统研究。结果表明：与原淀粉相比,添加0.1%的铝盐对豌豆淀粉凝胶色差无显著影响（p＞0.05）,添加0.5%及1.0%的铝盐能显著提高（p＞0.05）淀粉凝胶的亮度、硬度、胶黏性和咀嚼性,而对a*值（红绿值）、b*值（黄蓝值）、弹性和内聚性无显著影响（p＞0.05）。红外光谱研究表明,铝盐与豌豆淀粉相互作用没有生成新的基团,也没有改变淀粉分子的化学键组成,但添加量为0.5%及1.0%时样品红外谱图中吸收峰峰形及强度差别变化明显,多个吸收峰强度增大,说明铝盐的存在对豌豆淀粉的凝胶结构有保护作用。     

挤压对小米淀粉理化特性的影响

采用双螺杆挤压机在5个套筒温度和物料水分水平下对小米进行挤压膨化,然后测定产品中淀粉的理化特性。结果表明:与物料水分相比套筒温度对小米淀粉糊化度的影响较大,而对水溶性糖含量的影响相反。V区温度从165℃升至180℃时糊化度明显降低,物料水分从15%升至21%时水溶性糖含量降低。与套筒温度相比物料水分对特征黏度影响较大,其值在单位机械能耗(SME)大于420W·h/kg时不再随SME增大而进一步降低。RVA测定结果也显示挤压导致淀粉糊化和降解;RVA黏度随套筒温度升高而升高,直至195℃;随物料水分含量升高而升高,直至21%。     

Effect of gamma irradiation on physicochemical,structural and rheological properties of plant exudate gums

This study was undertaken to determine the effect of gamma irradiation on physicochemical characteristics of acacia, apricot and karaya gum. The moisture and carbohydrate content varied significantly (p ≤ 0.05) from 8.83–11.12 and 77.98–83.08 g/100 g, respectively, in native gums. Protein, fat and ash content also varied significantly among the gums (1.63–2.25, 0.09–1.10 and 3.67–5.72 g/100 g, respectively). Functional properties like water absorption, emulsifying, swelling and solubility index increased with the increase in irradiation dose (0–5 kGy). Viscosity of the aqueous gum dispersions measured using RVA decreased with irradiation under natural and acidic environments. Absorbance of the functional groups like –OH, –COOH, uronic acid and pyranose units increased upon irradiation in acacia and karaya gum as confirmed by FT-IR analysis. Irradiation had a pronounced effect on the rheology of acacia and apricot gums reducing their viscosity. In case of karaya gum, there was a transaction of gel-like solid behaviour to viscous liquid behaviour upon irradiation.     

干热处理辅助酶法制备多孔淀粉及其对淀粉微观结构和理化性质的影响

为了探讨干热处理对酶解制得多孔淀粉颗粒结构和理化性质的影响,采用扫描电子显微镜、傅里叶变换红外光谱仪、X射线衍射仪、比表面及空隙度测试仪、热重分析仪等对不同处理的淀粉进行测定,分析比较了干热处理(Dry heat treatment,DHT)对天然淀粉及多孔淀粉的影响.结果表明,经DHT的淀粉表面出现破损,相对结晶度减...     

冻藏对小麦淀粉理化性质及热力学特性的影响

研究了冻藏对小麦淀粉颗粒表面形态、理化性质、热力学性质及凝沉特性的影响。通过扫描电镜(SEM)检测冻藏小麦淀粉颗粒,发现部分淀粉颗粒表面有破损;对冻藏后的小麦淀粉溶解度、粘度、膨润力、蓝值等进行测定,结果显示冻藏后淀粉溶解度和粘度分别增大了48.6%、43.2%;膨润力、蓝值分别降低8.41%、28.5%;采用示差量热扫描(DSC)测定冻藏小麦淀粉热力学性质变化,发现冻藏小麦淀粉糊化热焓降低了47.3%,糊化温度起止范围降低了10.60%;凝沉值降低了47.2%。研究表明冻藏后的小麦淀粉颗粒形态,理化性质、热力学性质均发生了明显改变。      

Effect of industry-scale microfluidization on structural and physicochemical properties of potato starch

A recently designed “industry-scale microfluidizer” (ISM) was applied to treat potato starch, then the structural and physicochemical properties of potato starch treated at different ISM pressure (30, 60, 90, and 120 MPa) were investigated. As ISM pressure increased, starch granule size was firstly increased, and subsequently declined at 120 MPa. A remarkable destruction of starch granules was observed, and all the large granules disintegrated into irregular block-like structures after treatment at 120 MPa. Both crystalline and short-range ordered structure were progressively disrupted with the increase of pressure. The structural destruction was attributed to starch gelatinization, which depended on ISM pressure. ISM treatment could arbitrarily adjust pasting viscosity and increase setback value of potato starch. Moreover, moduli and mechanical rigidity of starch pastes were enhanced by ISM treatment. These results implied that ISM treatment could be a potential choice to modify starch containing large granules at an industrial level.Industrial relevanceMicrofluidization was an available physical technique to improve functional properties of starch. However, it was difficult for conventional microfluidizer to treat starch containing big granule sizes both in laboratory and industrial scale owing to the drawbacks of devices. A recently designed “industry-scale microfluidizer” (ISM) in our laboratory could be applied to treat potato starch containing large granules. This preliminary study gave important indications that the practical industrial applications of potato starch could be widen by safe and simple microfludization technology, and ISM may be used for processing whole grains flour to obtain nutritional products.     

Effect of cross-linking on the physicochemical and physiological properties of corn starch

Corn starch was chemically modified by cross-linking with STMP/STPP (99:1. w/w) and the physicochemical and physiological properties (in vitro and in vivo) of the cross-linked corn starch were investigated as a function of the degree of cross-linking. Cross-linking decreased the solubility, swelling factor, and paste clarity of corn starch. While the swelling factor was highly correlated with the degree of cross-linking (R² = 0.878), the X-ray diffraction patterns did not show any significant alteration in the crystallinity of corn starch. It was shown by SEM measurement that a black zone was observed on the surface of crossed-linked starch granules, which did not occur with native starch. When mice were fed the diets containing the corn starch with low (CLCS-5) and high (CLCS-12) degree of cross-linking (51.3 and 99.1%, respectively), significant effects on the final body weight, weight gain as well as perirenal weight of the mice (p < 0.05) were observed. Also, significant decreases in total lipid, triglyceride, and total cholesterol concentrations in serum were detected in CLCS-5 and CLCS-12 groups (p < 0.05). While total lipid level in the liver decreased with increasing degree of cross-linking, the triglyceride level was not affected by the supplementation with both of CLCS-5 and CLCS-12 corn starch samples.     

机械活化处理对绿豆淀粉理化性质的影响

为探究球磨机械活化处理对绿豆淀粉理化性质的影响,对机械活化后绿豆淀粉的颗粒形貌和粒度分布进行观察,并进一步对其热力学性质、糊化性质、溶解度、膨胀度、持水能力和冻融稳定性等理化性质进行测定。结果表明,淀粉颗粒形貌发生了改变,表面变得粗糙不光滑,形状不规则,淀粉颗粒粒度分布范围为2～200 μm,70%以上分布在20～75 μm区间,粒度中位径增大到43.09 μm,热焓值降低至2.32 J/g,糊化温度显著降低,衰减值及回生值分别为原淀粉的1/30和1/31,微细化绿豆淀粉具有较好的热糊和冷糊稳定性,溶解度和膨胀度随着温度的升高而增大,持水能力和冻融稳定性为原淀粉的3.2倍和2.0倍。